The present invention relates to industrial fasteners and more particularly to a plastic hole plug (closure plug).
In the manufacture of various panels, especially rigid thin plastic panels and sheet metal panels, holes are formed in the panel to be filled by a screw, rivet or other fastener. However, frequently the holes are left empty. For example, a refrigerator wall or an automotive body panel may be punched or drilled with holes which are used to attach devices. If the devices are omitted, for example, the device may be an optional device which is not selected, the panel would be left with an empty hole. It is often desirable that the hole be closed, so that the panel may have a better appearance and to prevent the passage of moisture or dirt.
A hole plug, to be acceptable, must be able to be retained in the panel, for example, it should stay in its hole even though the panel may vibrate or objects may be bumped against the plug. The plug must be able to fit in holes which are not exactly round and in holes which are "off-size", i.e., either too big or too little for the exact diameter of the plug. Furthermore, in a sheet metal panel the panel hole edge may have a sharp metal burr which may prevent the easy insertion of the plug into the hole. Some hole plugs, which are satisfactory in other respects, may be expensive because they utilize an excessive amount of plastic resin or because their design requires expensive manufacturing techniques.